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Finding the Fourth Proportional to 857.38, 1,286.07 and 280.25

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Solution

The fourth proportional to 857.38, 1,286.07 and 280.25 is: 420.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.38 : 1,286.07 = 280.25 : x
  2. Step 2: Convert to fraction form
    857.38/1,286.07 = 280.25/x
  3. Step 3: Cross multiply
    857.38x = 1,286.07 × 280.25
  4. Step 4: Simplify right side
    857.38x = 360,421.12
  5. Step 5: Solve for x
    x = 360,421.12/857.38
  6. Step 6: Final answer
    x = 420.38

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.